My opinions are based on my experience and they go like this: shooting a regular size AR or AK indoors is extremely loud. Now these were semi autos and I did not shoot them at the same time but from memory I would say the AR was stupid loud while the AK was insanely loud. And both caused some level of communication problems with surrounding people in the aftermath (the AK more so and for much longer than the AR if memory serves me right).
By contrast, 9mm rounds fired out a SMG with a 9 inch barrel never caused any problem communicating with other members of my unit regardless of how many rounds or shooters were involved. But that was a couple of decades earlier so there is is always the possibility that my ears might have become more sensitive -but I doubt so as hearing tends to worsen as we age.
All of the above were fired without a suppressor which seems relevant as the OP never mentioned he was going to use one. I personally do not care much for suppressors and won't use one for home defense. Clearing a house alone is enough of a bear of a dangerous job without adding a suppressor to the equation.
That's my 02 on this subject and worth exactly what you paid for it
